After a ton of searching, i think i finally found what is causing this issue. Lets start with the lua error.

Message: Interface\SharedXML\SharedUIPanelTemplates.lua:426: 'for' limit must be a number
Time: Thu Aug 29 04:13:06 2019
Count: 2
Stack: Interface\SharedXML\SharedUIPanelTemplates.lua:426: 'for' limit must be a number
Interface\SharedXML\SharedUIPanelTemplates.lua:426: in function PanelTemplates_UpdateTabs' Interface\SharedXML\SharedUIPanelTemplates.lua:412: in function PanelTemplates_SetTab'
Interface\FrameXML\CharacterFrame.lua:14: in function `ToggleCharacter'
[string "TOGGLECHARACTER0"]:1: in function <[string "TOGGLECHARACTER0"]:1>

Locals: frame = CharacterFrame {
0 =
selectedTab = 1
}
tab = nil
(for index) = 1
(for limit) = nil
(for step) = 1
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = "'for' limit must be a number"
GetTabByIndex = defined @interface\SharedXML\SharedUIPanelTemplates.lua:419

The "SharedXML" was throwing me off since a few mods were using this string. I had to find the issue in my saved variables.

Here is a pastebin of my wow pro saved variables file #1

https://pastebin.com/kifXAUcd

and Saved Variables file #2

https://pastebin.com/JaXMxtXu

edit: appears to be a unrelated issue. deleting my wtf folder fixed it.